Make hostNum empty when changing sync server

Should fix an error encountered when the user used AnkiWeb in the
past and receives a JSON decode error because an unrecognized
endpoint (/[somenumber]sync instead of /sync) doesn't return what
the client expects.

Closes #10, fixes #8.

README.md

@@ -58,10 +58,13 @@ Create a new directory in `~/Anki/addons21` (name it something like ankisyncd),
 create a file named `__init__.py` containing the code below and put it in
 `~/Anki/addons21/ankisyncd`.
 
-    import anki.sync
+    import anki.sync, anki.hooks, aqt
 
     addr = "http://127.0.0.1:27701/" # put your server address here
     anki.sync.SYNC_BASE = addr + "%s"
+    def resetHostNum():
+        aqt.mw.pm.profile['hostNum'] = None
+    anki.hooks.addHook("profileLoaded", resetHostNum)
 
 ### Anki 2.0
 

addon/__init__.py

@@ -1,6 +1,6 @@
 from PyQt5.Qt import Qt, QCheckBox, QLabel, QHBoxLayout, QLineEdit
 from aqt.forms import preferences
-from anki.hooks import wrap
+from anki.hooks import wrap, addHook
 import aqt
 import anki.consts
 import anki.sync
@@ -8,6 +8,8 @@ import anki.sync
 DEFAULT_ADDR = "http://localhost:27701/"
 config = aqt.mw.addonManager.getConfig(__name__)
 
+# TODO: force the user to log out before changing any of the settings
+
 def addui(self, _):
 	self = self.form
 	parent_w = self.tab_2
@@ -43,7 +45,7 @@ def updateserver(self, text):
 	if config['enabled']:
 		addr = text or self.customServerAddr.placeholderText()
 		config['addr'] = addr
-		anki.sync.SYNC_BASE = addr + "%s"
+		setserver()
 	else:
 		anki.sync.SYNC_BASE = anki.consts.SYNC_BASE
 	aqt.mw.addonManager.writeConfig(__name__, config)
@@ -52,6 +54,9 @@ def updateui(self, state):
 	self.serverAddrLabel.setEnabled(state == Qt.Checked)
 	self.customServerAddr.setEnabled(state == Qt.Checked)
 
-if config['enabled']:
+def setserver():
+	aqt.mw.pm.profile['hostNum'] = None
 	anki.sync.SYNC_BASE = config['addr'] + "%s"
+
+addHook("profileLoaded", setserver)
 aqt.preferences.Preferences.__init__ = wrap(aqt.preferences.Preferences.__init__, addui, "after")